According to a recent study, a child’s tooth unearthed from an old layer of a cave floor in Southern France belonged to a member of our species. If so, the tooth is now the oldest evidence of Homo sapiens living in Europe, and its presence means that our species shared Europe (or parts of it) with Neanderthals for at least 10,000 years. But other fossils from the site suggest that the Pleistocene tale of two species was more complex than we’ve realized.

Finding the first Homo sapiens in Europe

People lived at Grotte Mandrin, a rock shelter in Southern France’s Rhone Valley, for tens of thousands of years. Until roughly 54,000 years ago, those people were Neanderthals. In the oldest layers of cave floor sediment, archaeologists unearthed a child’s molar. Based on its shape and dimensions, the tooth once belonged to a Neanderthal child, which was exactly what paleoanthropologists would expect in a layer of sediment between 79,000 and 62,000 years old.

An adult Neanderthal molar from the next layer up, dated to between 69,000 and 56,000 years old, was also not startling to anthropologist Ludovic Slimak, of Université de Toulouse Jean Jaurès, and his colleagues. But a child’s molar unearthed from the next layer—somewhere between 56,800 and 51,700 years old—was a real surprise. The tooth’s size and shape was clearly not Neanderthal; when Slimak and his colleagues compared it to other upper second molars, they found that it fit best with very early members of our own species.

The baby tooth from Grotte Mandrin, lost in the dirt of the cave floor roughly 54,500 years ago, is now the oldest evidence of our species anywhere in Europe. (Here’s hoping the Pleistocene version of the Tooth Fairy rewarded the kid well for that particular tooth.) Previously, the oldest trace of Homo sapiens on the continent was a 46,000-year-old tooth and a few bone fragments from Bacho Kiro Cave in Bulgaria, unearthed in 2020.

Why we care

We’re interested in when our species got to Europe partly because the continent is one of the last places our species colonized (which is ironic in light of much more recent human history). Humans had been living in Australia for at least 10,000 years before the Grotte Mandrin child dropped its baby tooth. By then, only the Americas remained unexplored by humans.

While our species was the first hominin to reach Australia and the Americas, we weren’t the first in Europe. That’s another reason paleoanthropologists are interested in understanding exactly when, where, and how we first arrived on the continent. Understanding how long we and Neanderthals might have coexisted could shed some light on how the two species interacted and why the Neanderthals went extinct 40,000 years ago.

At Grotte Mandrin, fossils and artifacts in the layers of cave floor sediment that piled up after about 54,000 years ago tell us that our species didn’t move in and replace the Neanderthals in one fell swoop. Instead, Homo sapiens and Neanderthals seem to have traded places at the site a couple of times before the Neanderthals finally disappeared. That suggests that several waves of Homo sapiens ventured into Europe before one finally established itself.

The timing of those turnovers, and the kinds of artifacts each group left behind, hints at how the species may have interacted, at least in one area of Southern France. And Grotte Mandrin also suggests something about how our species first found its way to Europe.

From the sea, up the river, to the steppes

Grotte Mandrin overlooks the Rhone River, which is one of the largest rivers emptying into the Mediterranean Sea. The Rhone Valley also forms a natural corridor between the Mediterranean Coast and the steppes of Northern Europe. In other words, the people who lived at Grotte Mandrin were living along a perfect route for hunter-gatherers’ slow expansion from Africa, through the Levant, and into Europe.

Once our species got a firm foothold in the Levant, it’s easy to picture groups of humans gradually expanding along the coast of the Mediterranean, where the climate was relatively hospitable and food sources were plentiful. A large river like the Rhone would have offered access to freshwater fish and mussels, birds, and game for hunting, and it may have been very tempting for Pleistocene hunter-gatherers to follow the river inland and take shelter in places like Grotte Mandrin.

It’s probably no coincidence that some of the runners-up for the oldest Homo sapiens fossils in Europe are along the coastlines and rivers of Italy, or that Bacho Kiro Cave is roughly 160 kilometers from the coast, as the Pleistocene crow flies.

“Together, these data suggest that the Mediterranean basin, from the Levantine coast to the Rhodanian corridor, appears to have played a major role during the geographic expansion of modern humans in Western Eurasia,” wrote Slimak and his colleagues.

Trading Spaces: Pleistocene edition

Lush coastlines and river valleys, like the Rhone, weren’t just tempting to Homo sapiens. The ancestors of Neanderthals probably followed similar routes on their way into Europe around 400,000 years ago. When our species showed up, some competition for food, fishing spots, and shelter was probably inevitable. But we don’t know much about how that competition played out or whether violence or peaceful co-existence was more common.

We do know, of course, that our species was eventually the only hominin left standing; no Neanderthal fossils show up after about 40,000 years ago, and the Neanderthals’ trademark Mousterian style of stone tools vanishes around the same time. We still don’t know exactly how Neanderthals went extinct, but it’s reasonable to assume it was somehow our fault. It’s easy to picture a one-act play in which Homo sapiens arrive and take over Europe from the Neanderthals in one steady 10,000-year campaign.

But Grotte Mandrin and other sites tell us that in at least a few places, the story was much more complex. At a handful of sites in the Levant, fossils reveal that Homo sapiens moved into an area only to find themselves replaced by Neanderthals a few generations later. The population turnover eventually settled out in our species’ favor at the expense of the Neanderthals, but the Neanderthals seem to have won some local, short-term victories.

At Grotte Mandrin, Slimak and his colleagues found the first Homo sapiens baby tooth in a 56,800- to 51,700-year-old sediment layer called Layer E. It’s mingled with stone tools made in a style that has been found alongside fossils of our species at sites in the Levant, dating to about the same time. It’s pretty clear that at least for a little while, Homo sapiens lived here.

However, the next layer up, called Layer D because archaeologists are nothing if not creative, is somewhere between 54,950 and 50,050 years old—and the two molars and one tooth fragment it contains are from young Neanderthals. So are the stone tools, which are the Mousterian type made almost exclusively by Neanderthals. The next layer also contains Neanderthal teeth and Mousterian tools.

Stone tools of the kind associated with our species—this time a different type called proto-Aurignacian—don’t appear again at Grotte Mandrin until a sediment layer dating to 44,100 to 41,500 years ago. After that, the Neanderthals didn’t return.

https://arstechnica.com/?p=1835595